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Feb
22
revised SSH file transfers hang after ~700KB
Added a link to the bugfixed library to save readers' time
Feb
22
awarded  Supporter
Feb
22
comment SSH file transfers hang after ~700KB
Hey, nifty. Thanks for the pointer! Since we use Net::SFTP::Foreign on so many boxes without issue (though often v0.61), I just assumed the remote network was at fault here. Never suspected a bug in the library.
Feb
19
awarded  Teacher
Feb
11
awarded  Scholar
Feb
11
accepted SSH file transfers hang after ~700KB
Feb
10
answered SSH file transfers hang after ~700KB
Feb
10
comment SSH file transfers hang after ~700KB
Thanks, this was really close. I varied the Net::SFTP::Foreign::put() block_size parameter (default 32KB), but choosing smaller blocks translated into less data sent before the transfer stalled. There's a related queue_size parameter that controls the "maximum number of requests that can be concurrently waiting for a server response". It starts at 32. By cutting that down to 23, I finally got transfers up to 5MB to succeed. They fail with queue_size 24, so I'll probably back off to 16 for safety. Still not sure why this installation needs this adjustment, but it's working.
Feb
9
revised SSH file transfers hang after ~700KB
Removed "is this the right place" paragraph. This seems to be the right place.
Feb
9
revised SSH file transfers hang after ~700KB
Added MTU tweak results
Feb
9
comment SSH file transfers hang after ~700KB
Great suggestion. I played with ping -f -l and it looks like the 1500 MTU holds up from client to server. I used the netsh shell to clamp the VPN network interface MTU to 1280, but experienced the same stall. I also tried running the transfer over the physical interface with the MTU clamped to 1280 and the VPN disconnected--no luck there, either.
Feb
9
awarded  Editor
Feb
9
comment SSH file transfers hang after ~700KB
Actually, I did note that "the command-line sftp.exe client works properly." I've just now added a bit more explanation; sftp.exe file transfers succeed with default options. I've also tried Net::SFTP::Foreign without the keepalive options and got the same failure as before.
Feb
9
revised SSH file transfers hang after ~700KB
Added more words to "sftp.exe works properly"
Feb
9
awarded  Student
Feb
9
asked SSH file transfers hang after ~700KB